I really like parcel, in many ways for the same reasons I like jest. Trying to wire it all up yourself is *so* much effort, that I'm willing to spend a couple seconds on initial builds to account for it.
Similarly, Jest does such a good job at wiring up coverage, which is really a pain with say mocha.
I't a bit more pragmatic, and I still have to do some leg work. I'll probably start using v2 in the next few months. I tried an early beta and had some issues with it.